1. Technical Field of the Invention
This invention relates generally to communication systems and more particularly to communication devices using speech recognition within such systems.
2. Description of Related Art
Communication systems are known to support wireless and wire lined communications between wireless and/or wire lined communication devices. Such communication systems range from national and/or international cellular telephone systems to the Internet to point-to-point in-home wireless networks. Each type of communication system is constructed, and hence operates, in accordance with one or more communication standards. For instance, wireless communication systems may operate in accordance with one or more standards including, but not limited to, IEEE 802.11, Bluetooth, advanced mobile phone services (AMPS), digital AMPS, global system for mobile communications (GSM), code division multiple access (CDMA), local multi-point distribution systems (LMDS), multi-channel-multi-point distribution systems (MMDS), radio frequency identification (RFID), Enhanced Data rates for GSM Evolution (EDGE), General Packet Radio Service (GPRS), WCDMA, LTE (Long Term Evolution), WiMAX (worldwide interoperability for microwave access), and/or variations thereof.
Depending on the type of wireless communication system, a wireless communication device, such as a cellular telephone, two-way radio, personal digital assistant (PDA), personal computer (PC), laptop computer, home entertainment equipment, RFID reader, RFID tag, et cetera communicates directly or indirectly with other wireless communication devices. For direct communications (also known as point-to-point communications), the participating wireless communication devices tune their receivers and transmitters to the same channel or channels (e.g., one of the plurality of radio frequency (RF) carriers of the wireless communication system or a particular RF frequency for some systems) and communicate over that channel(s). For indirect wireless communications, each wireless communication device communicates directly with an associated base station (e.g., for cellular services) and/or an associated access point (e.g., for an in-home or in-building wireless network) via an assigned channel. To complete a communication connection between the wireless communication devices, the associated base stations and/or associated access points communicate with each other directly, via a system controller, via the public switch telephone network, via the Internet, and/or via some other wide area network.
Regardless of whether a communication device operates within a wireless communication system, a wired communication system, or operates independently, it may include speech recognition functionality. In general, speech recognition circuitry attempts to digitally simulate the human speech production system by creating acoustical filtering operations that operate on frames of digitally represented sound utterances.
Current embodiments of speech recognition systems include a sound front-end, a hidden Markov model (HMM), and a language syntax back-end. The sound front-end extracts acoustic features of speech (e.g., cepstrum). This allows the excitation information of the voiced speech signal (e.g., the cepstrum) and the dynamics of the speech system impulse response to be separately processed. The HMM block functions to determine a most likely utterance from the extracted acoustic features. The language syntax back-end functions to shape the utterances based on language syntax impositions.
While such speech recognition systems function to emulate speech, the acoustic front-end discards a significant amount of information regarding the speech of an individual. Therefore, a need exists for a speech recognition system and applications thereof that utilize additional information.